Seismic
Sedimentology for High-Resolution Hydrocarbon Reservoir Prediction: A Case Study in Cretaceous Qingshankou Formation, Qijia Area, Songliao Basin, China
Zeng, Hongliu¹; Zhu, Xiaomin²; Zhu, Rukai³; Zhang, Qingshi4
¹BEG, University of Texas at Austin, Austin, TX.
²China Univ of Petroleum, Beijing, China.
³RIPED, PetroChina, Beijing, China.
4Daqing Oilfield Company, Daqing, China.
For over four decades Songliao Basin has been the largest oil producer in China. Entering a matured and advanced exploration stage, geoscientists are increasingly focused on targeting thin (1-10m) and stratigraphic traps for reserve growth. Works on these subtle reservoirs using available well and 3D seismic
data are challenging. Multiple lithology types (sandstone, calcareous sandstone, shale, and limestone/marl) coexist in the main exploration interval, Qingshankou Formation, and complex and ambiguous
seismic
geomorphologic patterns are quite different from those that are more familiar in marine sediments.
This study was aimed at integrating seismic
lithology and
seismic
geomorphology for improved reservoir prediction. A new workflow was employed, which includes such key steps as 90° phasing of wavelet, establishing
seismic
chronostratigraphic framework, data frequency adjustment, petrophysical analysis, attribute analysis, stratal slicing, and
seismic
sedimentologic mapping by integrating core description, wireline log facies and stratal slices. Two key research issues are (1) how to recognize relevant
seismic
signal for
identifying
the best reservoir among different lithology types, and (2) how to optimize
seismic
attributes and visualization methods to map
depositional
systems at high resolution and thin-bed level.
We recognized a total of 8 high-order sequences
in 300-350 m thick Qingshankou Formation. Each sequence is composed of a LST at bottom and a HST at top, which are basic mapping units for the study. Core and wireline log analysis revealed fluvial-dominated deltaic facies, including distributary channel, mouth bar, delta-front sand sheet, prodelta, and lake. Vertical stack of alternative LSTs and HSTs explains certain lithology/impedance/amplitude associations for different systems tracts. Channel forms, relative impedance, and fine-scale facies boundaries were interpreted from different
seismic
attribute displays and were superimposed for comprehensive facies interpretation. In the best cases, sandstones as thin as 1-2 m can be predicted.
AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012